Some of these may sound cliché but these tips still work to increase followers.

1. While producing the content keep a mix of posts which attract new followers and retain the existing ones.
2. Grow one platform with the help of another one (promote your Instagram posts through WhatsApp or a YouTube video or any other platform)
3. Be consistent (Your people should know what to expect from a you)
4. Engage the existing followers in your stories
5. Use different set of hashtags
6. Do occasional giveaways (not too much of it, as this might not bring your target audience)
7. Stick to your niche and keep the content quality high
8. Collaborate with people in your niche
9. Solve some problems of your target audience or just help people in DM
10. Keep an Optimistic mindset. Do it for a bigger purpose than just attracting followers